RTS Configurations

The RTS can be built in several different ways, corresponding to global CPP defines. The flavour of the RTS is chosen by GHC when compiling a Haskell program, in response to certain command-line options: -prof, -threaded, etc.

So for example, libHSRts_thr_debug.a is the version of the runtime compiled with THREADED_RTS and DEBUG, and will be linked in if you use the -threaded and -debug options to GHC.

The ways that the RTS is built in are controlled by the GhcRTSWays Makefile variable.

Combinations

The following combinations are allowed:

DEBUG with anything

PROFILING only with NO_REGS, USE_MINIINTERPRETER

OLD ways

The following ways are bitrotted and currently don't work (GHC 6.6):

PAR, GRANSIM

Parallel Haskell
GHC option: -par
RTS suffix: mp, mg

TICKY

Ticky-ticky profiling used to be a separate "way"; you had to rebuild all the libraries and the RTS for ticky-ticky profiling,
just like ordinary time/space profiling. This isn't the case any more: you can link modules compiled with -ticky
against modules or packages compiled without it. Since 6.12.1, the -debug RTS version also include ticky-ticky
support, and there is no separate RTS version for ticky. If you use the -ticky flag when linking a program, it implies
-debug.